The Black Widow Spider (_Latrodectus_ spp.): This spider is found in the south and east of Spain. It is black with red markings on its belly. The bite of a black widow spider can cause nausea, vomiting, muscle spasms, and even death in severe cases. However, deaths are rare.
The Brown Recluse Spider (_Loxosceles reclusa_): This spider is found in the arid and semi-arid regions of Spain. It is brown with a dark brown fiddle-shaped mark on its back. The bite of a brown recluse spider can cause skin necrosis and even amputation in severe cases. However, deaths are rare.
The Six-Eyed Sand Spider (_Sicarius_ spp.): This spider is found in the sandy areas of Spain. It is yellow or brown in color with six eyes arranged in two rows. The bite of a six-eyed sand spider can cause skin necrosis and even death in severe cases. However, deaths are rare.
The False Widow Spider (_Steatoda grossa_): This spider is found throughout Spain. It is black with a red hourglass shape on its belly. The bite of a false widow spider can cause mild pain and swelling, but is rarely dangerous.
The Mediterranean Recluse Spider (_Loxosceles rufescens_): This spider is only found in Southeast of Spain. It is a shy spider that is rarely seen by humans. The bite of a Mediterranean recluse spider can cause skin necrosis and even amputation in severe cases.